Dewaxing of oils



- any wax-containing oil, including both vegetable oils liquidfractiomhoiling rangeunder 20",, c onsists mainly' of buta'ne andpentane. i The next fraction, petroleuni ener t n oi such as diesth'ebasis of volatility; yiscosit Forsqme ypeset petrole fur erdistillaticnuml sweated or f shalloyy Fatented May 2, 1961 ice benzineor other solvents and chilled, permitting a further separation of oilfrom paraffin. The latter is then filtered hot, through charcoal andcast into blocks, re-

2,982,692 sulting in, the familiar crystalline parafiin utilized forpaper coating, candles and pharmaceutical ointment bases.v

The oil filtrate from paraflin presses is steam distilled,

and the residual oil purified by filtration through bleaching clays,yielding high grade lubricating stock oils and heavy mineral oil.(Textbook of Organic Medicinal and 0 Pharmaceutical, Chemistry-Wilsonand Gisvold; 3rd'ed.,

19.56,. I. B. Lippincott, PP- 60, 61.)

' Vegetable oils and waxes Fats and oils are found widelydistributed innature, This invention relates to processes for dewaxing oils in bgththe plant and animal kingdoms. Waxes likeand refers more particularly toa process for dewaxing wiseare naturalproducts but .difier slightly fromthe fats and oils in their basic composition. Whereas the fats and oilsare mixtures of the glycerides of various, fatty I acids, the waxes aremixed esters of higher polyhydric alcohols other than glycerol withfatty acids. Petroleum is the ma or source of hydrocarbons. v The 7various natural Oils. 'difi in regard to their fatty composition ofcrude petroleum is very complex. It 1 s vaciigame-11;: Thgsg agids fallwithin 1 the Saturated made up of hundreds of dlfiterent compounds. 'Inaddlries, asexe p fi d by stea q id 3 141 are the basis tion to smallpercentages of nitrogen, sulphur and oxy f lthe: nqmhying n a 2) mono lSeries with" gen-bearing compounds present in, some petrolepms,;thedqubl'enbond betwefiniicarbpns as illustrated by oleic hydrocarboncontent may include parafiins, straight and 5 1 and m (3) l lfmi' Serieswith more than on? I branched-chain types; traces of olefins and otherunh doublebond ascsemp fiedhy linoleic a d o enic. saturated aliphatichydrocarbons; naphthenes or cycloacids) The latter w Glasses f' id beingunsammted paraflins of the generic formula C H hav ng five or fumiih thesqmidtying and drying qils, according t thg six carbon atoms in thering, with parafiiruc or naphthetl c amounts f unsatumfiqn prespmy hChief rconstitugmsi side chains and aromatic 'or benzene hydrocarbons oft the vegetable 1 1 a the 16 andfl8 c apbQn i genenc fmnula Highermlicular 9*- Coconut oil is u ique in, that it consists o es e o ch.drocarbons include cycloparafiin-aromatic structures with Short .cflrbqnchain acids, 2 and 1 4 carbcgn acids paraffinic side chains. Thecomposition varies with the, baing presentpin greatest m sourcePennsylvania oils have a high content ofparaf- 85 ThejactbrV-detemnining whether Qf thesfi com fi i hydrocal'bmls h. r P raifi spounds is, termed a fat or an oil is merely its melting M -C n Oils haves r naphthenic l ll?" point. 'The, degree 0t unsaturation of the acidsinvolved: 7 matic hydrocarbon n st n s i 353 51 .95? effectsthe meltingpoint of the-ester mixture, thefmorey P Y i I 4 unsaturatedacids givinge'stersvyith lower melting points; T commel'clal e w of Y bQ fractionsthese. being the chief constituents, of, the oilsl g si t of a series odistillations crude Pe o eum .The're aret wo-b-road classifications foroilsi edibleiand. and subsequent washings and purificatiqnfir ..Thelowest inedible The various edible..oi ls, cottonseed,{olive, ,soybean,corn, etc, are'ernployed for salad dressingS,.other tableuses,andiorcooking purposes- Thehydro'genated fats forcqoking and baking,such asCrisco and .Spry may include'aj widevariety-of vegetablecils,such aslcote tonseed, peanut, and soybean, sincefthefhydr'ogenatingprocessv removesthe color, flavor and odo 'r of the original DEWAXING 0FoILs j HardinB. McDill, P.O. Box 654, Houston, Tex. No Drawing. FiledJune 26, 1957, Ser. No. 668,041 4 Claims; c1. 195-3 and mineral oils, bythe use of enzymes or yeast.

Petroleum waxes I he boilipg jge 0. s c iefly [p'entane' a d hexane. iaq nsi e a t erteusireldemand may. be,

pl lsqte o r a b in r n 0 9215. ease,

line embraces QQ WidQ range of hydrocarbons 'saturated. Source 7 1 y Ianduns tur ted, branch d and stra ht; chain. up; to

I la zsv. f.

Ker sene sf h hydrocarb a ras ie 'cqlle at fwm 175. 9 2 5 d mp is rz HzsIQ-61611154:

pounds. Gas oil, collectedabove. 275, includes, light -'Thetwo generalmethods conventionally. employed in ohtaininggvegetable,tats andioils;are expression and sol-' vent, extraction. fottdnseed oil is-us editorshortenings, margarine and .dalad or cookingfoils. Corn oil, is usedalmost-exclusively as a Saladioili Only coconut oil of I low free'fattyacid content is employed tonedible pure, Bean'ut oil is hydrogenatedandrefi'ned foruse ture or margarine, salad and cooking oils e-vegetable shorteningsr The finest; gradeofss' ve urn 213 393 Soybea iusho ld, bu n ng i eavier furnaee' p s' g nq: r ger.

istics.

steam' sup 'r heating yields thehaWQdistillalte, from which ane's;lubricating:oils andsome light Y in naturalgl y occur-.

a rena-nan dis illat on, s..-.u.t i ed as,

yielding fvga'qr' distillate wig itli g but a similar .wax m ay' be' obQlfhe Chemical Process Ind l 1 W. ll press deflecting par arat-ion of:oil and wax. The

Ozocerite is composed of ester waxes, such as montan wax, straight chainhydrocarbon waxes such as paraffin wax and branched chain hydrocarbonwaxes. Montan wax (C H O comprises esters of montanic acid.

' w 7 Dewaxing oils V N The dewaxing of oils is a critical problem bothin the fields of vegetable oils and mineral oils. In the purifying orrefining of vegetable oils, and especially edible vegetable oils, theextraction of waxes from, the individual oils has not developed ,assuccessfully as has this process in the mineral oil field and severaloils have not. been fully exploited as to their commercial usesbecauseof this problem. Many of these waxes are very ten'aci-. ous intheir adherence to their oil bases or carriers and resist evensuccessive attempts to extract the wax. Rice oil,-for example,-;isonewhich contains a relatively large percentageof wax which is extremelydifiicult to remove andthus has not yet been completelyevaluated as toits. potential uses because of this fact, commercially. The methodsofchilling and settling and solvent extraction have been attempted inremoving or attempting to remove waxes-fromvegetable oils. These havemet with varying degrees of success, as previously noted.

As to the mineraloils, in the refiningof petroleum, it is well knownthat crudes from certain geographical regions have more or less waxtherein. 'Various processes have been developed to dothis, includingchilling, settling and centrifuging and solvent extraction employingvarious solvents. While'it must be "admitted that, largely/the removalof waxes from petroleum andmin- I eral oils is presentlysuccessfullyaccomplished, such removal is' achieved at-great expense and requiresmuch time, as well as expenditure of energy.

The main objectionto the presence of wax in petroleum products is itsrelatively high congealing temperature which'interferes with the free,circulation of oil inthe engine. After circulation is established,,theengine performance depends upon the true viscosity of the oil and, notthe pour point. At temperatures of complete miscibility, the presence ofwax inthe oil may even be beneficial. Dissolved wax improves theviscosity index, lowers the carbon forming tendenciesand has a minoreffect on the other oil properties. Nevertheless, due to the temperaturedifficulties, in the majority of petroleum products, the presence of waxis regarded'as a severe disadvantage and problem.

Therefore, an'.object of theinvention is to provide a process ofdewaxing oils which will swiftly, easily. and cheaply remove waxes'fromwax-containing oils;

Another object of theinvention is to provide such a 7 process which willdewaxoils of either vegetable or mineral source, including theediblevegetable oils petroleum oilsl I p I Another object .oftheinvention is to provide'a methodi of dewaxing wax-containing. oils ofeither. vegetable or mineral origin by the additionof relatively .smallquantiand the 'ties of easily obtainable chemical substances .and biochemical substancesvthereto; p I

Another object v ofthe invention is to'provide' such' a; process fordewaxing wax-containing, oils wherein there is no problem of separatingthev dewaxingcliemical sub origin which will substantially andcompletely remove waxes from these oils whereby to obtain color andclarity inthe dewaxed oils at least equal to the best dewaxing processesnow existent and in most cases far superior thereto.

Another object of the invention is to provide a process for dewaxingwax-containing oils of either vegetable or mineral origin which willremove waxes from oils which have previously not been successfullydewaxed either experimentally or commercially. 7

Still another object of the invention is to provide a treatment processfor crude mineral oils and petroleum with yeast wherein not only is thecrude dewaxed but at least a partial separation of the hydrocarbonfractions is achieved without the application of heat to the crude orthe use of expensive distillation equipment.

Other and further objects of the invention will appear in-the course of.the following description thereof.v

I have discovered that waxes can be removed from. oils, by fermentationtreatment employing yeast and/or, enzymes. The waxes removed .includethe paratfinic. waxes from petroleum distillates or crudes and, as well,

' the mixed esters of higher polyhydric alcohols with fatty acids whichmake up the waxes from vegetable oils, and particularly, ediblevegetable oils. 3A specific example of the dewaxing process applied on alaboratory scale operation utilizing an edible vegetable oil is asfollows:

t (1) /6 oz. of yeast is dissolved in 50 cc. of water and sweetened witha little sugar to assist the fermentation action (2 oz.) whichtakesplace in the succeeding steps. (2) The foregoing cc. solution isadded to 5 gallonsof crude rice oil.

(3) The foregoing mixture is agitated vigorously for several ;minutes atroom temperature (approximately 80 F.).

(4) 6 drops of pepsin are added and agitation is continued for severalminutes.

. (5) Agitation is discontinued. The mixture is allowed to stand for aperiod varying from a minimum of 24 hours to a maximum of approximatelysix days during which continued fermentation causes almost all of the:

wax to settle out.

I (6) The b'ulk'of the wax-free oil can be decanted from,

the vessel and the balance islseparated from the wax.

and yeaSLresidue by centrifuging; thev oil obtained by centrifuging canbe added to that which was decantedf (7) The oil ,thusrecovered isessentially wax-free but,

as a precautionary measure, it may be retreated in the samemanner; asthe original crude oil, beginning with the addition of the sweetenedyeast solutionand pepsim: followed 1 by agitation, settling and;finally, separation of any additional residue from the supernatant oil.The process as'ap'plied to mineral'oils, either'crude or distillatefractions, is exactly thesame as previously de-- scribed as regards theorder ofsteps'and the yeast, sugar-- and,pep'sin. lhe results. will 'beexactly the same, al-

* thoughthe time intervals may be slightly different. Therefore, I will'nqtre'peat the indiv'idualsteps just recited, butv incorporate themwith thedifierencesnoted in this para-1.

'. graph to provide specific, examples of the application stances fromthe treated oils after the dewaxing; p'rocessf I Still another object ofthe 1 invention is; to" provide a process for dewaxing wax-containingoils of feither vegetable or mineral ,originfwherein-the addition ofcer-f tain byproducts of enzymatic activities tolt he oil to be, dewaxedeffectively r moves a large proportion of the; wax in the oil'intheifir'st' .stage iof the processa'nd where-" in the'oil, after thefirst separation maybe retreated by" :--Yet "another ob ect o'f' tmyention'is *to: provide; a?

' process for dewaxing oils of'ither 'vegetable (Jr-mineral 7 the same'pro'cessto remove yetf fur'ther oil so that-the f of the method tomineral oils.

'{I fhav'e discovered .that the critical factor in Z the pepsin additionis "theenzyme peptase for pepsi'nl'm pepsin, the. enzyme, is remarkablein having an 'isoelectric point which is atleast'as far acid as pH Theoptimum arr; for the 'enzymeis.also irrthejstrongly acid region, being'3 l. 5 to 2.5 Elixir of pepsin is; composed of, the followingi;v

Pepsin g ams"; 35f, Citric acid do 12* Sodiumphosphat, do 7 1s.Distilled water i m 300 Gree q -i And additional-distilled wateflb1,000=cc."*f a My process 'will dewax oil fromthe following vegetableseeds, nuts and the like: cottonseed, peanut, corn ing: rice brancontains to 18 percent 'rice polishings, 20 percent of oil. The yield ofwax recovered, if fecovered from the crude rice oil, is somewhat lessthan 2 percent or less than .04 of one percent on a bran basis; The oilmay be at least partially dewaxed before refining with acid and alkaliby the use of a De Laval separator or basket centrifuge. The oil canalso be at least partially dewaxed by theme of evacuated unglazedporcelain cylinders coveredwith filter cloth. A good yield is obtainedat 20-25'' centigrade with suction at 50 mm; mercury pressure. Thesestudies of rice bran wax were made on the tank settlings from crude ricebran oil. (Cousins, E. R., et al., Journal of American Oil ChemicalSociety, vol. 30, 9-14, 1953.) C

Other art'states that the crude wax-containing glycerides may beseparated from crude rice oil by wintering at 20-25 C; and thentreated'with a solvent such as. 5 percent methanol in commercialN-hexane to effect a sharp separation of soluble and insoluble parts.Without the use of the solvent, the wax from the tank'settlings cannotbe eifectively separated by filtration methods. Studies have been madeof the use of acetone and isopropanol as extracting solvents for tanksettlings. It should be pointed out, however, that, despite thesestatements in the art, there is no commercial method to satisfactorilyextract rice oil Wax from the rice oil and yet leave a clear, properlycolored oil which will not cloud on reduction of temperature due tothepresence of yet additional Wax therein.

The chemical composition of rice bran wax comprises esters of waxy acidsof 22, 24 and 26, carbons combined with alcohols of 26, 28- and-30carbons. It also contains small amounts of Wax acids of 2.8, 30 and 32carbons. The softer constituents contain both saturated and unsaturatedacids of the range C'14 to C-20. The wax also contains sterols.

The crude rice wax may be at least partially purified by washingrepeatedly with methyl alcohol, ether, and, finally, chloroform. Thisprocess yields a substance which is an ester mainly composed oftetracosanoic acid and myricyl alcohol (C H OH) with small amounts ofsaturated acids and some unsaturated acids.

Rice Wax analysis characteristics: percentage of free fatty acids2.1-7.3, average 3.8; iodine number 11.1-19.4, average 15.2; percentageof unsaponifiable 55.6-67.0, average 58.1; saponification number56.9-104.4, average I 80.7; percentage 'of phosphorus .01-.18, average.09;

percentage volatile matter .38-2.94, average .94; melting point (drop)degrees centigrade 75.3-79.9, average 77.9;

average made to improve them by removing the-undesirable fattyconstituents inherent in crude Wax.

The biological generic term for yeast is Saccharomyces cerevisiae. h

My present concept of the nature of my process is L that thejenzymes inthe yeast and the fermentation products may satisfy some of theunsaturated bonds of the The known art on dewaxing rice oil reveals thefollowcarbon bond in the lubricating .oil wax, Such a reaction may'c'hangethe crystalline structure of thecomponents of the wax and inthe'higher molecular weight compounds, the crystals may become denser andheavier. This theory is not intended to be limiting.

Yeast enzymes (a partial list) ('1) Di-astase-conversion of starch tosugar;

(2) Cytase-conversion of cellulose to sugar;

(3) Invertaseconversion of polysaccharides to monosaccharides;

(4) Maltaseconversion of maltose to dextrose;

, (5) Milibiase-conversion of 'milibiose to dextrose;

(6) Lactase-conversion of lactose to dextrose;

(7) Zymase contains four elements-alcoholase, oxidase, endotriptase andpeptase, these are analyzed below.

(7a) Oxidase-enzymes of this class are considered to be active in theoxidation changes induced in a number of organic substances, such assugars, aldehydes, alcohols and fats. The oxidase (oxidase) secreted byacetic acid bacteria is Well known for its energetic oxidation ofalcohol to acetic acid in the manufacture of vinegar. Yeast oxidase isassumed to .take an active part in building plasma and autofermentation.Its presence is indicated by the heat generated when air is passedthrough finely divided yeast.

(7b,) Endotriptase-the proteolytic endo-enzyme of yeast is able-tohydrolyze the protein molecule to amino acids and basic substances.It'is considered to be active in the digestion of protein food, theformation of plasma and in regulating the protein content of the cell.Endotriptase is precipitated from yeast juice .with alcohol but cannotbe separated from invertase. It ismost active at 45 C- i-n .2% solutionof hydrochloric acid and is destroyed at 50 C. Endotript-ase plays animportantpart inautofermentation of yeast.

(7c)v Peptase-this enzyme acts upon the proteins of malted grain,changing them by hydrolysis intopeptones and polypeptides. Its action ispromoted in the mash by. the presence of a small amount of lactic-acid.Peptase may be extracted from green malt and is most active attemperatures ranging from 38 C. to 54- C. It is destroyed at 68 C. Y I

The following conditions must be met for the process to be effective. Inthe first place, the yeast must be living. In the second place,carbohydrate which the yeast will accept as food must be added tomaintain the fer- 1 mentation action. Thirdly, the additional peptase orpepsin rnust be added. The live yeast and excess peptase must beagitated in the oil. Finally, a certain amount of settling time mustpass. When these conditions are satisfied, the process which I havedisclosed will effectively and completely dewax oils of the variouskinds set forth previously in one or more treatments.

The best test for determining the presenceof wax in vegetable ormineraloils. after dewaxing processes is,

either freezingthe oils'or subjecting thecils-to successively varyingtemperatures ranging from very cold to or cloud under conditions ofseveralyvaried temperatures.

"least six such layers.

(1) The bottom layer, is a yellowish one made of what appears to be theyeast fillers and carriers'which are lower alcohols in therice wax' andthe unsaturated hydrogenerally starches of various types. j I

(2) Immediately above the preceding layer I find a blackish, dark layerwhich very probably are impurities of various sorts together with,probably, asphalts and the like. a a V t (3) Above the preceding layeris what appears to be a kerosene-gasoline layer which is generally about25 to 30 percent of the total volume of the treated settled crudepetroleum and which has a grayish color after the practice of my method.

(4) Above the foregoing layer is a Whitish layer which I am unable toidentify at present.

(5) Above the foregoing layer is a layer of generally brownishwax.

(6) Above the wax layer is a layer which appears to be and which I taketo be gums of various sorts somewhat similar in appearance to the waxpreviously mentioned; 1

(7) At the top of all these layers is found the clear, dewaxed, degummedoil.

These various layers can be decanted off or drawn off by variousconventional means. The exact composition and components of thesevarious layers I do not know completely at this date, aside from theabove speculations, but it is my belief that my method, as well asproviding an efiicient dewaxing process, is applicable as well as acrude oil component separating process or fractionating process whichrequiresno application of heat or expensive apparatus and equipment. Theprovision of such a separation in the oils treated is thus one of themain features of my invention.

From the foregoing it will be seen that the invention is one welladapted to attain all of the ends and objects hereinbefore set forth,together with other advantages which are inherent to the method.

It will be understood that certain features and subcombinations are ofutility and may be employed with-. out reference to other features andsubcombinations. This is contemplated by and is within the scope of theclaims.

, As many possible embodiments may be made of the invention withoutdeparting from the scope thereof, it is to be understood that all matterhereinabove set forth yeast and a carbohydrate the yeast will accept asfood thereto cause a physical separation of at least a portion of thewax from the oil.

2. "A processof treating an oil containing at least one wax thereincomprising adding living Saccharomyces cerevisiae yeast, peptase inaddition to any peptase in theyeast, and a carbohydrate the yeast willaccept as food thereto to cause a physical separation of at least apor-' tiori of the wax from the oil, separating the wax produced by thefirst addition from the oil and adding living Sdcchkzrmyces cerevisiaeyeast, peptase in addition to any peptase in the yeast, and acarbohydrate the yeast will accept as food again to the separated oil tocause a physical separation of additional wax from the oil.

3. A process of treating an toil'containing at least one wax thereincomprising adding living" Saccharniyces cerevpisiae yeast, peptase in.addition to any peptase in'the yeast, and a carbohydrate the yeast willaccept aslan energy source thereto, agitating the oil containing theyeast, peptase and carbohydrate 'to mix them thoroughly therein andcause a physical separation of at least a'portion'of the wax from theoil and removing the wax produced from the oil.

-4. A process as in claim 3 wherein the wax removal process comprisesletting the wax produced settle and then decanting theoil therefrom.

References Cited-in the file of this patent v UNITED STATES PATENTS76,974 Barton Apr. 21, 1868 1,753,641 Beckman Apr. 8, 1930 2,316,621-Renner Apr. 13, 1943 2,742,398 Zobe11' Apr. 17, 1956 V FOREIGN PATENTS VN 7 465,111 Great Britain Apr. 26, 1937

1. A PROCESS OF TREATING AN OIL CONTAINING AT LEAST ONE WAX THEREINCOMPRISING ADDING LIVING SACCHAROMYCES CEREVISIAE YEAST, PEPTASE INADDITION TO ANY PEPTASE IN THE YEAST AND A CARBOHYDRATE THE YEAST WILLACCEPT AS FOOD THERETO CAUSE A PHYSICAL SEPARATION OF AT LEAST A PORTIONOF THE WAX FROM THE OIL.